Modern Mining September 2018

SHAFT SINKING AND RAISEBORING

handful of companies worldwide able to under- take deep shafts.” Other shaft-sinking contracts completed within the past several years include the sink- ing of the main and vent shafts (both to over 800 m) at Wesizwe’s Bakubung platinum mine in the Western Bushveld, the main and vent shafts (both of medium depth) at Kalagadi Manganese in the Northern Cape, and the main and vent shafts at Sasol Mining’s new Shondoni colliery. The Shondoni shafts, as is the norm in South African coal mining, are rel- atively shallow but have substantial diameters of 11,7 m and 9,1 m respectively. Says White: “Our thrust into the shaft mar- ket was highly successful but, of course, new shafts tend to be associated with new ‘green- field’ projects and, over the past several years, projects of this type have been thin on the ground. So, we’ve now found ourselves in a situation where we are busy with just one shaft – Shaft 1 of Ivanplats’ Platreef project near Mokopane in Limpopo Province. We need to move more into contract mining and mine development and we are working hard on this. We have an impressive track record in these areas so there is no question of our ability to handle work of this type.” On the subject of Platreef’s Shaft 1, White

(Moolmans is probably Africa’s biggest surface mining contractor), the underground business is less so, reflecting the fact that the under- ground mining industry has been in recession for the past several years, with very few capital projects underway. White makes the point that his predecessors in the management of the underground busi- ness saw a huge future in shaft sinking and made a conscious decision some years back to position Aveng as a major player in the shaft- sinking field. “If you go back a decade, Aveng was in shaft sinking but had no real experience of deep shafts,” he explains. “The contract that established its credentials as a company able to compete head on with the specialist deep-shaft contractors was No 4 shaft of the Konkola Deep project on the Zambian Copperbelt, which is more than 1 500 m deep. “The performance we put in on this contract led to further awards, with perhaps the most notable being the sinking of a 950 m deep, 11 m diameter vent shaft at Codelco’s Chuquicamata copper mine in Chile. The seismicity of the ground is such that the shaft has a 450 mm thick concrete lining, which is very unusual. We undertook this project in conjunction with a South American partner, and it fur- ther cemented our reputation as one of only a

The Platreef site showing the headgear of Shaft 1.

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September 2018  MODERN MINING  41